IT’S essential for underground mining that adequate ventilation systems are in place.

The Ventchoke system is a low cost mechanism that can control  secondary ventilation circuits underground with any vent duct installation.

After 30  years working underground, UVS chief executive officer Darren Gilbertson took matters into his own hands to improve the ventilation issues he had experienced, and developed Ventchoke.

Designed and innovated over four years, it has been through strict condition testing on-site, including 13 months initial research and development on a Kalgoorlie underground mine site.

The Ventchoke offers a solution to the problem of ongoing repairs by eliminating costs on maintenance.

It will work continually without attention for a minimum of 12 months, offering massive saving to mines on the cost of repairing problems caused by the inefficient method of ropes and pulleys.

This adds extra exploration and production dollars to the project.

Mr Gilbertson has made continual improvements to the innovation, tweaking the design to create the efficient and reliable product that is available today.

This completely unique, globally patented product is successfully  improving health and safety and cutting costs on mine sites around Australia.

“My main concerns centred around the health and safety of the workers as well as the time and money savings a new innovation could provide,” Mr Gilbertson said.

He was determined to create a better system that would ensure fresh air flow in tunnels where it was needed.

The use of ropes and pulleys continually require repairs which cause ongoing production halts as well as creating an unsafe working environment.

The Ventchoke alternatively can easily divert, reduce, or stop airflow completely with the turn of a lever.

The system allows for secondary ventilation circuits (vent ducting) to be easily shut off, and ventilation to be redirected to other active headings in the mine, by one person from the ground.

The ease of use escalates mine efficiency incrementally.

The device can be installed around any existing ventilation duct and ensures that the people working in certain areas of an underground mine are receiving the maximum amount of quality air, while the other, un-manned areas of the mine are not wasting fresh air when it is not required.

Ventchoke will work continually without attention for a minimum of 12 months without maintenance.

Blasting scenario without Ventchoke

Secondary venting is essential in a blasting situation, where air needs to be directed to a specific heading.

Without the aid of Ventchoke, to control the secondary venting circuits, the air will go to the closest headings first and the ones furthest away will get less .

The worker who wires in and fires the charges (shot firer) has a half hour window between shift changes to complete his job.

To charge the face or heading, he will be lifted in a diesel-powered charge-up rig (Normet or Charmec) with the engine at full throttle, emitting highly carcinogenic diesel fumes into the backs, where he, will breathe them in as he is charging the holes in the face.

If shotcrete is also being used in the ground support system, and has only freshly been applied within the last four hrs or so, ammonia fumes are released, where they rise to the backs and are breathed in by the charge up crew as well: definitely not a good scenario.

If the oxygen in the tunnel is low when he arrives in the drive, he needs to attempt to divert the ventilation to that heading.

Time is of the essence and his KPI’s are often dependent on production.

Before he goes up in the basket, he uses the rope and pulley system to choke off the vent bag; however, the ropes are tangled and it won’t tighten enough.

His two options are to complete the job without adequate ventilation, or to contact the one service crew that most mines run, who will be busy on some other maintenance or repair job and will take some time to arrive and complete the job.

According to Mr Gilbertson, the more likely scenario is that he will put expediency before safety and lay the charges, putting his health in jeopardy.

Scenario with Ventchoke

The charge-up crew enters the heading, and to increase the oxygen and ventilation in the drive, he checks that the other headings are free and unmanned, then activates the Ventchoke by turning the air header tap .

In under a minute, all the available fresh air is flowing into his heading, and the charge up crew are able to complete there job in a fully ventilated environment.

Construction

The Ventchoke is hard and durable with a solid three layers covering the bladder.

It is constructed from heavy duty PVC and joined with high frequency welding for the ultimate in a robust structure.

12Kw and 8Kw high frequency welding machines at the UVS workshop use radio waves to activate the PVC molecules.

A pneumatic press then moulds the crossed layers of PVC together, creating the incredibly strong vent duct structure as it cools.

The ventchoke design has a large air flow but low pressure.

The device is filled with 18psi but holds 5-6psi internally.

In spite of the low pressure, when fully inflated it is as solid as concrete.

The 18psi pressure required is easily sourced from any mining compressed air line available.

A small amount of leakage, around two to four cfm, is built in to prevent over inflation.

A spring mechanism with the springs customised and manufactured by Boynes Springs in Perth, WA, controls the Ventchokes dump valve rate.

To prevent wear from trucks loaders and Jumbos, for tight drives, the Ventchoke has a heavy ripstop layer on the base circle.

The tough material contributes toward the longevity of the system.

How it works

The Ventchoke is easily installed at the join between vent bags.

It slides over the join and is held in place by eyelets and clipped onto a continuity wire.

The bag is joined back together and the Ventchoke is connected by air hose to one of the air headers in the tunnel.

Inflation occurs within 30 seconds and deflation in 50 seconds, creating a secondary ventilation control system at minimum cost.

The low pressure air (18-20 psi) fills the Ventchoke tube which applies an inward force on the ventilation ducting – this is done via a set air pressure regulator that is built into the Ventchoke.

The pressure in the Ventchoke constricts the vent ducting and stops airflow through the ventilation.

There is also a dump valve on the Ventchoke for easy deflation when required.

Many benefits to mines 

The pneumatic choke is very powerful.

Installing the Ventchoke eliminates the need for ropes and pulleys.

This antiquated system is a major cause of health hazards for underground mine workers.

The use of ropes and pulleys cause several issues which halt production and require repairs, such as jamming and wearing away the bags.

Ropes knotting often creates a situation where the vent bag is unable to be tightened correctly, which increase the likelihood of workers breathing in contaminated air.

Other issues like flapping, splitting, shredding and holes in the vent which then needs to be replaced occur regularly.

Downtime can be extensive by the time the service crew arrives, halting production for indefinite amounts of time for every incident.

The Ventchoke offers a solution to ongoing repairs, eliminating costs on maintenance.

It will work continually without maintenance for a minimum of 12 months.

This saves the mine having to waste exploration and production dollars on the cost of repairing problems that have been caused by old inefficient methods.

For a low cost of $2000, the mine can install a part that comes with a full year’s warranty, with no moving parts, no electronics and no maintenance hours.

The Ventchoke can be installed into any ventilation system without additional computer cables or electronic parts that are prone to corrosion in the hot, salty tunnel environment.

VOD systems can also benefit from the installation of Ventchoke to enable a faster re-entry after blasting.

By supplying better ventilation with a system that is quick to install, easy to use, and robust enough to work in underground mining conditions, Ventchoke has the capability to improve operations on every mine site.

It is available in three regular sizes: 1067mm, 1220mm, 1400mm and can be custom made to any size needed

For more information:

Phone: 0408034786
Email: [email protected]
Website: uvs.net.au

Check out the New Animation Video on Facebook at Underground Ventilation Systems@Ventchoke or Linkedin

 

 

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